A gorilla named Kidogo balances on a rope at the zoo in Krefeld, Germany
This grinning hyena looks more than pleased to kick off 2013. Photographer Bridgena Barnard captured the sight in South Africa's Kgalagadi Transfrontier Park.
A cheeky lion cub tries, and fails, to grab his mother's tail in the Masai Mara, Kenya, Africa. British photographer Ed Brown says: "This little guy had way too much energy and always wanted to play, somehow mum, without even looking, kept her tail just out of reach!"
This porky prairie dog in Arizona looks in desperate need of a diet. It may have taken the idea of fattening up for winter just a tad too far.
Three three-week-old lion cubs are displayed at Szorako-Zoo in Gyongyos, Hungary
A gorilla named Kijivu holds her nine-day-old baby at Prague Zoo, Czech Republic
Two orangutans huddle together to keep warm during a cold spell at Taipei Zoo in Taiwan
Two chimpanzees hug each other next to a radiator to keep warm at Qingdao Zoo in China
A sea lion paints a Chinese character reading "the Serpent" at the Hakkeijima Sea Paradise aquarium in Yokohama, suburban Tokyo, to mark the forthcoming year of the snake
Elephants munch on Christmas trees in their enclosure at Berlin's Zoo
A keeper holds a bullfrog during the annual stocktake at ZSL London Zoo
Penguins assemble to be counted at London Zoo's annual stocktake
Keeper Sarah Hall helps count some of the meerkats as part of the annual stock take at Bristol Zoo
A cheetah cub gives another cub a high-speed piggy back as they play on the savanna in Ngorongoro Conservation Area, Ndutu Plains, Tanzania. Paul Souders photographed them larking around in front of their mother.
Photographer Ed Brown captured these two lion cubs play-fighting on the Masai Mara in Kenya
British tourist Joanne Mockford and Kelly and Michael Cocks walk with white lions at the Protea Hotel Ranch Resort during the "walking with lions" tour in Polokwane, South Africa
Two lions named Tiny and Manzi laze in the sun at the Wildlife Heritage Foundation in Kent, England
A tiger grabs a chunk of meat underwater at the Six Flags Discovery Kingdom in Vallejo, California